Wearing Grey
by StreamingViking
Summary: Self-Insert Fanfic: Summoned as a Demi-Servant he participates in the Fourth Holy Grail War as Servant Avenger as the man who wears Armour of The Grey Man.
1. Chapter 1 - Man In Grey

Blinding light filled his vision, for a single moment, he was blind and death.

He tried to sort his thoughts so that the sensory organs he possessed could start working again.

He noticed, he was standing up, his body rigged.

But something was wrong it, felt like he was wearing something that covered his entire body, clinging to his skin. But it was like with a single thought it could be removed or changed.

His vision started to clear. Sound could be picked up by his ears once again.

He could hear a voice speaking, it sounded young filled with enthusiasm and excitement like he had just accomplished a great feat.

Where was he didn't know?

He wanted to stay still until his vision was clear and could probably see.

He could hear the sound of static, a television that hadn't been connected to its antenna. He hadn't heard that sound in a long time.

Where the hell was he?

He heard a second voice, but it was muffled like somebody trying to talk through a covered mouth.

He could see now see where he was.

It was a barely lit room that looked like somebody's living room.

And in front of him, was… In front of him was…

Raged flared through his body, like surging fire as he recognized who was standing in front of him.

Ryuunosuke.

Serial Killer, child murderer. Lunatic and psychopath, so many words could be used to describe the filth of a human being in front him.

Most all Master of Caster, Bluebeard.

He realized where he was and fear entered his heart, but it only lasted for a moment as he took notice of what was in front of Ryuunosuke.

A child.

A scared child, frightened out his mind tears streaming down his face, as he tried to scream through his gagged mouth.

"Hey, Mister Demon I got a meal for you right here, afterward let's go out and kill some more."

Rage overtook the fear he felt as he heard what the serial killer had said.

He had killed this boy's family, and now Ryuunosuke wanted him to kill the boy believing him to be a Demon.

His appearance must have changed by the summoning for how else would he think that _HE_ was a Demon.

At that thought, a single word rang throughout his head.

 **Avenger**

Ah, he understood now, he had become a Servant through the summoning, Pseudo or Demi he didn't care right now.

Now he just wanted Ryuunosuke to die.

He was Avenger now, and he had to fulfill his duty as one.

He wasn't the Cavern King that much was obvious, but still, he would do the job of the one that was true vengeance at this moment.

Knowledge rushed through his head and like a well-used muscle he always had, for many years he pulled on the string and sword appeared in his hand.

He swung the blade, and Ryuunosuke's head fell to the floor, blood sputtering out his neck as his body to fell to the floor a second later.

Avenger moved to the boy quickly and pulled him into a hug.

The boy was almost catatonic as he was stiff in Avenger's grip.

Avenger lifted the boy up and was now carrying him as he cried.

They needed to get out of here.

As Avenger held the crying boy he was able to see his reflection in the window, it was unclear, but the form he saw easily recognizable as the one that had been shown in the latest story portion of Grand Order.

Antonio Salieri.

The rival of Mozart, accused of killing the man himself. And so he had become an Innocent Monster twisted by rumors.

New knowledge entered his mind, the knowledge of music.

Avenger moved his left fingers up and down, and the sound of a playing piano could be temporarily heard.

The magic was cast, and the child fell asleep in his hands. But it was still a tragedy that had occurred here. Avenger could see the dead bodies of the boy's parents, laying on the floor. Their blood had been used in the ritual meant to summon Gilles de Rais.

And speaking of Servants.

Avenger looked down at Ryuunosuke's body and at his hand.

He could not see the Command Seals on either of his hands, were they perhaps on Avengers perhaps he was his own Master.

He would have to check that later, now he had to call the police and let them know what had happened here.

He moved through the house and found the room that was the boy's room. He removed the sleeping buy's binding and placed him down his bed, pulling the quilt over his body letting sleep for a little time before the police arrived.

Avenger called the police using the houses phoneline and left the house behind, quickly heading into the center of Fuyuki city using the supernatural speed the Wailing Armor gave him.

He came to a stop at was a for sale house, it would make for a quick place to sleep for the night. So, in the morning he could plan for the events of the fourth Holy Grail that starts tomorrow night with the fight at the docks.

Avenger removed the red armor that covered his body from head to and got a lock at hit more human appearance. One that had been significantly changed. He was very fir now compared to before, and his eyes were a deep shade of red that glinted in the bedroom mirror he was currently looking at. But he was not naked under the armor but wore the sleek suit and scarf that Salieri did in his second Ascension art. Command Seals were upon his right hand when he removed the glove that covered it.

"Glad to see that you're befitting from this union my Master/host." Avenger heard a voice speak, not from around him but inside his head. And now in the mirror, he could see a second person looking directly at him.

"Salieri," Avenger said in response to the man.

"Yes, I have to be him now since, with our union Master, you're the Man in Grey now. Servant Avenger." Salieri stated his mouth moved with words. "A truly unique situation we're in don't you think. Human and Servant fused together as one to participate in a Holy Grail War, and from the knowledge running around inside your head, a now defective Grail. THAT CANNOT GRANT THIS ONE'S WISH. Sorry, my emotions got the better of me." Salieri apologized.

"It's fine," Avenger said that was truly his existence now. He had to be Servant Avenger he had to win the war, a war where the most powerful heroes participated in, one where Tokiomi had summoned Gilgamesh.

"Yes, the King of Heroes, a troublesome opponent we have, but do not worry Master, all have a weakness we just need to exploit," Salieri said, and Avenger agreed. Gilgamesh was powerful, stronger than all heroes, he wielded the very ideas and wisdom of mankind via his Gate of Babylon. But he was prideful, and that pride could be used against him. "Yes, and he is also one few in this war that can eliminate our fellow Avenger stuck inside the Grail."

"Yes, Angra Mainyu is a problem one that was difficult to deal with but, Gilgamesh has tools needed to deal with it. Though the option of having Saber, destroy is still an option if it comedowns to that." Avenger suggested.

"It is, but let's save further planning for the 'morrow. You need to sleep Master, your body is not used to handling the power of the Man in Grey, even in it's improved state." Salieri said.

Yes, Avenger felt o' so tired right now. He took off his clothes and made use of the bed, he fell asleep almost immediately.

Xxx

"Did, you have to use my talents for something like begging." The astral form of Salieri said in front of Avenger said as he ate his breakfast with the money he had made using the man's borrowed music talents as a Servant. The People had thought it also a magic tragic as he had played the piano without using a piano.

They had certainly been impressed, and he had made about twenty dollars worth of yen before the police had arrived.

Illegal street performance and all that, he could survive through the Grail War if he kept doing that to get money and use the on sale house to sleep in, and shower as the thing had running water.

"Hey, I'm not a full Servant, so I still need to eat," Avenger told him in a low voice, as nobody heard him. He was in the corner of the Japanese Breakfast restaurant. But there was no need to be shouting.

"True, but it feels like begging, and its something I'm uncomfortable with."

Right, rich guy. "It's really not, more like selling a service, and people decide to give their own price for the product." He told the pianist.

"Hmm, an acceptable. So, Master what is the plan for the War, what do you wish to use my powers for?" Salieri asked Avenger.

And he did Avenger had several things he wanted to accomplish in this War. One had already been averted with the massacre done by Ryuunosuke and Bluebeard, due to not having been summoned with Avenger taking his place.

The second thing was the salvation of Sakura, Avenger wanted to save the innocent girl from that disgusting pit. The Zouken formerly Zolgen, it would be mercy he would deliver on the old man from Russia. If Avenger had been sent to this universe as a normal human, he would have tried for Paracelsus as a Caster.

But he was the Man in Grey now, he had to deal with the powers he had been given, by whatever entity had made this happen. For it couldn't have been Zelretch he would have asked first. And Avenger also needed to make sure that nothing would go so wrong that the Counterforce would prune it.

First, though there was the fight between Diarmuid and Saber at the docks tonight, where everyone else would show up to.

There Avenger would make his first performance.

The rest he could plan for later, and he needed a plan for Zouken. He couldn't do a Crow and just start kidnapping people, he didn't want to be a copycat. Well, maybe he should try and steal Kiritsugu's Contender and Origin rounds.

"If that is what you wish to my Master, my power is yours to freely use, though if we do manage to survive this insanity, I shall try to get you a better taste of music." He said as he vanished.

Avenger was going to find a way to get back at Salieri for that comment he had good taste in music. That being almost no taste at all as that allowed him to enjoy as much music as possible.

He really wished he had his phone, why did he have to be stuck in 1994, the only music player on the go was a bloody Walkman.

Xxx

There were several things Avenger liked about his new status as a Demi- Pseudo Servant. His enhanced body, senses and the fact that he could feel calm and not frit like he normally would. And it allowed him to kill Ryuunosuke without breaking down into a sopping mess. If there were any mental changes Avenger approved of it was that kind. And speaking of the Serial Killer, the police had found the scene he had been summoned to, and boy was okay but heavily traumatized due to what had happened. But the boy whose name had turned out to be Kaneki.

Avenger had snickered a bit at that.

He had said, that he had been saved by Devilman.

Avenger had actually shed a tear at that. He had never expected that to have happened.

Which with that name had caused him to realize a side of effect of his fusion with Salieri. He could perfectly remember the tune of every single song he had heard and played it perfectly using his magic.

The man was just that good.

To the annoyance of the composers, Avenger had chosen a particular tune to reveal himself with.

He was currently hiding in the shadows between the containers looking at Lancer who had just sent out his challenge to all the other Servants.

Which Arturia would respond to in few minutes, Avenger was preparing himself.

Oh, poor Kayneth if you had to summon an Irish spearman, you shouldn't have summoned the one known best for NTR his king's wife. If you should summon an Irish spearman, you summon Cu or Fionn, not freaking Diarmuid. If you couldn't do that go for Aife, or at least try for Scathach. Well, he was going to learn that he had summoned a Servant that was not very compatible with him soon enough.

It didn't take long for Saber to show up with Irisviel, the woman who was a walking tragic due to her nature as the Lesser Grail. Her life was limited and the next few days would be some of her last ones on this earth. There was nothing Avenger could do to stop that from happening. If he had been a Caster Servant of the highest grade, he could have done something to stop it. But he wasn't so that particular fate would play out like normal. But he would make sure that Illya would be happy, by making sure Kiritsugu survived the war and saved. Or if not Avenger would do it by his own means.

Avenger watched as Arturia and Diarmuid commenced their duel, to the eyes of human the five-minute-long battle would be fast to a humans eyes. But to Avenger they moving in real time as he was able to see each and every one of their moves as they swung their weapons about.

But so it came to an end as Arturia was cut by Gae Buidhe the golden spear that dealt wounds that could not heal.

And that was when Iskander made his debut to the other Servants. "Hear me Heroic Spirits I have seen your glorious battle and so invite you to join my side in conquest, for I am Iskander King of Conquerors!" The giant of a man hollered.

 _Sorry, but I like your younger form better, as you can be a fucking asshole when you're summoned like this._ Avenger thought as he heard the Rider Class Servants declaration.

"Sorry Rider I have already sworn my allegiance to my Master," Lancer answered.

"And I could not possibly follow a fellow King." Responded Saber.

"Damn, that's too bad. Well, then how about our fellow Servants that watched your glorious battle from the shadows, show yourself before a King?" Rider challenged us.

"Two mongrels calling themselves kings in my presence." And there was the glorious golden man himself as he appeared on top of light post.

Well, it was time for Avenger to do his thing.

He summoned his blade and began moving it up and down his armor-clad hand like he was playing a violin.

 _Blood red shadow creeping. Who is that? Who is he? Can it be the devil?_ _The Devilman. The Devilman!_


	2. Chapter 2 - Music At The Docks

_This night has gone from bad to worse._ Kiritsugu thought as he looked through the scope at the Archer Class Servant that belonged to Tokiomi that had appeared on top of the light post. His form clad in the same golden armor when he had killed Assassin.

Who Kiritsugu still believed was alive, for he could not believe Kirei Kotomine would waste his Servant like that. No Kiritsugu believed it had been a performance, a way for Tokiomi to show of his Servant and make everybody else think that Assassin was dead so he could lurk in shadows. Without anybody being wiser.

For that was what he would have done.

But that wasn't his biggest concern right now.

He was terrified for Irisviel's safety, now that Archer was here. If he fired a volley of his weapons like he had done against Assassin at Saber the risk of Irisviel dying was higher than he would ever have like.

Kiritsuu contemplated using a Command Seal to have Saber run away with Irisviel as fast as possible. But Command Seals were precious resources, and he only had three of them, and they had to be used with careful usage. But for his wife, he would use all of them.

That was when Kiritsugu heard it.

The music.

Somebody was playing music.

It was familiar music to Kiritsugu's ears, it was a song that he hadn't heard in many years. An unbidden memory rose to the surface of his mind.

A memory of smiling boy sitting in front of a small tv as the hero defeated the villains while the boy cheered on hoping to be a hero just like him. Just like.

Kiritsugu crushed the memory, and he turned his scope towards where the sound was coming from, and where he saw another Servant jump out from between the containers and landing on another light post right in front of the Golden Archer. The Servant looked severely out of place among the others with seemingly a non-human body. He took a quick look at his Parameters and saw that they were good for not being one of the knight classes. Lowest being C and highest being A in Agility. So this would be a slippery one.

"Kiritsugu I have the Master of Lancer in my scope do I take the shot?" Maya asked over the radio.

"Wait, for now, only fire when the others Servants have left or if he decides to run away before that happens," Kiritsugu answered his assistant.

"Understood Sir."

The radio went silent on the warehouse he was laying across. His eyes on the unusual music playing Servant.

"Devilman," the words left his mouth as the Servant finished playing.

Xxx

Avenger bowed to the others as he finished playing his piece.

"I have half-mind to skewer you for interrupting me and playing such infernal music." Gilgamesh threatened him.

"Come now Archer that was a wonderful piece from our fellow Servant, that was the song of a hero. Now, are you going to introduce yourself? Caster if I'm to presume right? And will you join my army?"

"Sorry I don't Iskander follow show stealers, I had planned to be tonight's entertainment, but somebody decided to barge in and take the spotlight." That got a laugh out of the Rider. "And I'm sorry to hear you didn't like my song Archer, but is there something else that I can play that the King of Heroes, would approve of?" Avenger asked, revealing the identity of the golden Servant and that got a reaction from all the others.

As they realized what kind of opponent that they could face in the war.

"So, somebody is able to recognize my glory on the spot I commend you Servant, so I shall forgive you for the song." Gilgamesh seemingly forgave Avenger.

Guess that put him in a good mood. "I appreciate it, your Majesty, as for who I am. I am a Servant of Vengeance, I am Avenger!" Avenger introduced himself, and as he did, he saw Irisviel's face turn to stone. Well, that should mess with her mind for a bit, and it made it clear that she knew about the previous summoning of Angra Mainyu. But there was also a thought of concern Avenger had, and that was the lack of Berserker. Kariya should have already called upon Lancelot and ordered him to attack Gilgamesh.

But he hadn't, and that was concerning, had his presence already changed events without his knowledge. That could potentially be troublesome.

Avenger would have to deal with that later.

"Tell the truth Servant!" And that was Kayneth opening his stupid mouth. "There are only seven Classes of Servants you have to be either Berserker or Caster. Lancer take him down."

Avenger heard the squall of fear that came from Waver hiding in Iskander's chariot.

"My magi of this time sure are foolish speaking like they know everything." Commented Gilgamesh, and delivering a sick burn to Kayneth's pride, making the magus growl that could be easily heard. "Hear me, Servants! I have turned my eyes upon you and found most of you as prober amusement. So, I shall fight against the last of you in combat." At that, the King of Heroes went into spiritual form, and Avenger laughed internally. He had not expected that to happen, but it seemed that no mad dog here, he would be in a significantly better mood.

"Ah, it seems that this night did not go as planned. Now Saber, Lancer, Avenger. I shall not interfere with your duel. Now Master, watch as Servants fight to their fullest." Iskander said as he dragged Waver up for all to see. The young magus was beginning to severely regret participating in the war. Especially now that he had to confront his former teacher, the man was going to kill for stealing his catalyst. Maybe he had already forgotten about him and wasn't able to recognize him.

"Waver Velvet." Or not. "So, you were the one who stole my catalyst, I shall teach you the true meaning of combat between Magi later after Lancer kills your Servant." Kayneth threatened him and Waver swallowed the ball of spit that had formed in his throat.

"So, you were going to be my original Master? If so I would never have followed a man like you who hides in the shadow doesn't stand by their Servant in battle, like my own and Sabers. But where is your Master Avenger? Is he to hiding somewhere here?"

Avenger chuckled as he heard the question from Iskander. "Sorry, but I'm my own Master now." He answered and the meaning of his words.

"You killed your Master?" Arturia asked me shock on her face.

"Of course I killed my summoner, my Skills allows me not to need one, besides he was scum, so the world is now better off without him," Avenger told them the truth. "Now when I think that we've talked enough, now let's dance!" He shouted as he jumped off his light pole and landed a few from Lancer.

He smirked beneath his armor as he utilized his Wildfire Skill. He moved his sword over his hand like before, music was produced but also where Lancer stood he was cut by several fiery slashes.

Saber cursed internally as she witnessed the medium range that The self-proclaimed Avenger Servant possessed. It would be troublesome to fight against if he could just deliver attacks like that. If she was going to fight against him the first place for it would be nice to finish her duel against the Knight of Fionn. She knew that most tactical option would be to just the two of them fight each other, and it would be best if Lancer lost so that cursed wound she had been inflicted with disappeared.

"Irisviel, should we retreat for now?" Arturia asked her proxy-Master.

"Yes, it would best if we retreat, he can tell us the result later, or your wound will give confirmation," Irisviel responded back.

Arturia gave her a nod before taking a quick look at the fight between Avenger and Lancer.

Just in time to see the red Servant almost impale Lancer with a thrust of his sword.

Avenger swiped to the side with graceful movements like he was dancing instead of fighting. And that really was he was doing, despite the shape of the sword. The knowledge he gained from Salieri in terms of combat wasn't usual sword techniques for a long sword like this. These were rapier techniques, for he had been taught by d'Eon in life, due to the relationship with the royal family and having the French spy as a friend. That was something that had surprised, Avenger when it really shouldn't have. Salieri was a Frenchmen and all important French people from that time period basically knew each other.

While Lancer did have greater skill with his spears than Avenger with his sword, along with a having higher agility and Eye of The Mind. Avenger would win the proves of the current physical match.

For he had an advantage over the spearman.

He knew the rhythm of Lancer thanks to viewing the fight between Saber and Lancer.

Diarmuid was now his instrument that he could free play like a Master, not without difficulty, but he had a sheet he could follow, even if he missed a few notes.

Such was the power of music and sound.

Along with another thing he could do.

His sword flared with magical energy, that if one looked closer at it, one could see it _Vibrate!_

Avenger thrusted his sword at Lancer's head, but the man managed to dodge and counter cutting him with Gae Dearg. An unforeseen obstacle he had not thought about as it could cut through the Wailing Armor and damage him. He could fix it up, but it cost energy to do so every time it was cut, and the wounds were starting to accumulate.

And the Lancer knew that, and that was why he thought he would win, but that would not be the case.

Avenger's sword struck a metal container instead of the Celt's head.

He turned around quickly and hit Gae Buidhe with his sword the Lancer being sent back a little.

"Sorry, Lancer but our duel is about to end as we seem to be down to only your Master, along with Rider and his Master as our audience, and this play has gotten stale," Avenger stated.

"You speak with words of confidence Avenger, you have taken more damage than me, and my Master has been able to heal my wounds, while that Armor of yours is only thing allowing you to fight and soon it will crumble. This fight will end, and I shall be the winner, but know this, this has truly been a great duel."

"You're wrong about that Lancer, you're already dead," Avenger responded.

"What!" Lancer said, and that was when he heard it. A high pitch sound that seemed to be ringing that came from two places. One was from behind Avenger, the second source was from he his golden spear.

It was a second later heard the pitch reach it high and when the container Avenger had before seemingly exploded. And a second later the spear in his hand followed damaging his hand, making it look like a broken mess.

Leaving Lancer with only one working hand and one spear.

Diarmuid was in shock as he looked at the remains of his destroyed spear.

"How, how the hell did you do that?" Was the only thing he could say as he turned his eyes to look at the person that had _broken_ his Noble Phantasm.

"Quite, simple it is something called resonance demolition, using frequencies and vibrations to destroy objects. It probably wouldn't have if your Noble Phantasm had been of a higher Rank." Avenger admitted, but what he didn't admit was that it had been a gamble and he hadn't been sure it would have worked. Heck, he was surprised it had on the Yellow Rose. But he had been able to pull a Scaramouch. "And like I said this is over," Avenger said, he rushed forward with all his speed and thrusted his sword right into Lancer's side That was when dark energy quickly began to twist around it before being unleashed.

That was the end as Avenger blew out the entity of Lancer's left side. To bad Diarmuid, didn't have Battle Continuation, unlike a certain, other Celtic man, if so he would still have been able to fight instead of dying on the spot. He had wanted to use _them_ to finish of Diarmuid, but he didn't want to reveal all of the cards he could play.

Visibly on the outside Avenger was calm and collected as whipped his sword of Lancer's blood.

But internally he was screaming of joy, as he realized he had fucking managed to defeat Lancer and the second night of the War, drastically altering the way things were going to go now. If he could do that he could now certainly do what other thing's he had planned.

Next stop was the Matou Mansion to rescue Sakura.

"Master of Lancer, I advise you to leave Fuyuki City and this harbor right now, before the Magus Killer still here decides to but a bullet in your head for good measure."

That was when Avenger heard the sound of a gun being fired and when the sound of metal hitting metal.

Guess Kayneth had been smart enough to bring his little orb of Mercury with him.

Avenger heard several more shots being fired as he turned his head to look at Waver and Rider. "I hope you enjoyed tonight's number King of Conquerors, next time I shall bring an even better symphony.

"It was an exquisite performance Avenger, shame about Lancer, would have liked to see him finish his duel with Saber. So I hope your performance against her will be as twice as grand. Come now Master, let us return to base and strategize!"

At that rider's chariot began to move pulled by its divine bulls into the air.

Waver screaming in fright.

Avenger chuckled as he heard the young magi.

Avenger had changed the future, by making it, so Kayneth was still alive, and probably survive escaping the city. Unless Kiritsugu decided to blow up the hotel prematurely. If so he would have some serious grudges to avenge.

 _One Heroic Spirit down five more to go._ Avenger thought as he jumped into the night air, humming a tune as he refueled his mana tanks for healing.

Xxx

A devious smile was on Caster's lips as she looked at the image she had scryed upon her the reflection of her water-filled cauldron.

"Miss Caster have you found somebody that can help Uncle yet." Caster looked through her veil at the purple haired young girl that was no higher than the length of her knees

"I do indeed have my apprentice, and he seems to be heading towards us at this moment. So let us give him a welcome." Caster told her.

The girl stood up on her toes so too look at the reflection turned image. "Wow, he looks like one of Onii-Chan's manga superheroes the girl commented in wonder.

And Caster couldn't help but smile at the girl's cheerfulness that had seemed to have been violated out of her by the worm. Oh, she despised the thing when she had first looked upon the mockery of a human being, and for wasting such a magical potential in the girl had, by making her go through that. Now, Caster had fixed her up but kept the hair as it was a much better hair color than the black one.

Xxx

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	3. Chapter 3 - The Sound of Others

Tokiomi sat at his table the light of the moon shining through the window as he read the report Kirei had sent to him that concerned the battle that had happened at the docks. Their plan truly had been a success as Assassin now could spy and act unhindered

He took a sip of his wine as he got to the section that concerned a specific Servant.

Avenger.

The Class was familiar to Tokiomi as it had been described in his grandfather's journal about the happenings of the Third Holy Grail War sixty years ago. It had been an extra-class summoned by the Einzbern that had replaced the Berserker Class. His grandfather had only seen the summoned Servant once when it thought the Edelfelts Sabers and lost horribly, being the wars first casualty. In addition, it had also had been a horrendously weak Servant with having the lowest parameters of all the summoned Servants.

But apparently, this one was different with not having been summoned by the Einzbern, it was not weak as it had managed to beat Lancer, whose true name was Diarmuid in single combat. With its power over seemingly fire and sound, a difficult opponent for any Servant that was not his own.

And speaking of Archer.

Tokiomi raised his eyes from the report to the golden clad Servant that had finally returned. "I hope you enjoyed your walkabout, your Majesty?"

"I did indeed, this Holy Grail War might turn out to be worth my time," Gilgamesh said as went into Tokiomi's vine cabinet and took out one of his bottles and drank straight from it.

He could replace it later, it was a worthy sacrifice if it meant that the King of Heroes would listen to his words.

"So, your Majesty do you think that any of the remaining Servants will be worthy opponents?"

"No, none them would be worthy to face my full might, but Saber, Rider, and the Avenger might relieve my boredom."

"So if I may ask your Majesty, do you have any insight into the Servants?" Hoping that Archer had useful information about the Servants as _that_ Noble Phantasm could inquire some unique information. Even as restrained as it was at the moment.

Hopefully, most about Avenger as he at the moment was the War's greatest unknown besides whichever Servant the Matou had summoned.

"You've been an accommodating host, so far, so I will give you some interesting information. Avenger is not fully a Servant." Gilgamesh told Tokiomi which lit up his curiosity.

"What do you mean by that, your Majesty?" He asked.

"Avenger is ordinary human that has been given, the power of a Servant. He would be a Demi-Servant a very rare thing to happen. Most of the time it would result in a fusion of personality, and so they would become a Pseudo-Servant. The Heroic Spirit is still within the human, but their personalities are separate."

Tokiomi let himself have an internal smile at that. Now he knew more than all other Masters. "Thank you for the information, your Majesty, now I need to contact Kirei and have him, have Assassin follow him."

"Do not bore me with your scheming Tokiomi, I shall be out exploring the city." At that Gilgamesh disappeared into spiritual form.

Tokiomi took another sip of his vine as he stood up, as he needed to contact Kirei about their next move.

Xxx

Arturia felt a sigh of relief as the car came to a stop and she exited the vehicle, her feet touching solid ground.

She was never going to let Irisviel drive, ever again.

Besides Irisviel's insane driving the normally peppy and talkative woman had dead silent and serious during the entire drive. Despite her inquiring her charge about her wellbeing, she had just been told, that she would explain when they got back to the castle.

"Irisviel, can you finally tell me what has made you so concerned?" Saber asked as the homunculi exited the driver.

"Inside." Was all she said, as she walked with large strides through the castle's doors and into their base.

"Irisviel, please tell me what has you so concerned?" Arturia asked once again as they took a seat at the massive dinner table, a few rooms into the castle.

"It's Avenger," Irisviel admitted

"Yes, he was rather a surprise to be sure, he might be an abnormality, but he shouldn't be a stressing point for you Irisviel," Arturia said.

"Saber, Avenger, is not supposed to be summonable, at least outside one being called by the Einzberns, we summoned one during the last war replacing the Berserker Class, and he was horrendously weak, and was the first to die. But this one isn't as he managed to beat Lancer, who you had trouble with."

Yes, The Avenger had defeated Lancer as Saber had felt her wound heal up as they drove back to the castle. And that fact had saddened Saber a bit she would have liked to have thought the Knight of Fionn once again.

"Well, Irisviel, if you think he is going be a problem for the Grail War, let's call Kiritsugu and find a way to deal with him?" Arturia suggested.

Xxx

Avenger ran through the street or on top of the roofs of the houses of Fuyuki with all his might to get to his destination as fast as possible.

He had gained the location of the Matou household, during the day before the battle at the docks, or Warf as was the proper name for it.

Avenger had expected Berserker to show up, and when to control the Berserker with his music, traumatize Saber a little bit, and then talk to Kariya about saving Sakura.

But that hadn't happened, and now he was concerned.

He would save Sakura, for she did not deserve her fate, ever since he had seen that scene in Zero of Sakura laying that pit of worms it had haunted him.

"When, save her Master, avenge her innocent and let them hear your anger, you have my full support. Much of me have been twisted into that of a monster, but I know children are precious, and such a thing should never have happened. Burn that worm to a crisp." Came the voice of Salieri.

His immaterial body floated at Avenger's side as he talked words of vengeance into his ear, though he was much better than a devil, to say the least about the edgy pianist.

"Oh, I will," Avenger stated the simple fact as he came to a stop in front of the old western mansion.

He could hear and feel several Bounded Fields around the old building.

But something was off, he could hear the sound of literal despair and anguish that was coming from the mansion that had been turned into quite the literal den of Evil.

Avenger was about to break the magical defenses around the house when he saw the front door open out, and Avenger's mouth dropped beneath his mask.

He had never expected this possibility to occur, and it did seem he had replaced Berserker and not Caster.

"Hello there Avenger, I am Servant Caster please come inside my Master, and I wish to discuss an alliance with you." Said Morgan Le Fay, the half-sister of the King of Knights. Dressed in a black and blue cleavage showing dress, wearing a dark veil over he face and blue crown on her head.

Well, Avenger had nothing really to lose, and he knew he could beat her even within her Territory. "I accept the offer, my Lady."

xxx

A/N:

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	4. Chapter 4 - Alliance

The interior of the Matou Mansion was just as Western as the exterior.

As Morgan let Avenger to where her Master was definitely Kariya and not Zouken. For he could hear many sounds within the Mansion and there was one lacking he had expected to hear in this place.

The sound of insects. Avenger couldn't hear a single wing beat, only the sound of a crackling fire from beyond the door he and Caster were approaching, along with the sound of children talking above them.

Strange.

Avenger was sure that Shinji was out of the country during the Fourth War, but it seemed he was chatting happily with Sakura.

Who sounded happy and not dead inside.

And the chance of him making the alliance with Morgan rose exponentially as it seemed that she had saved Sakura from the pit.

"My Master is inside the study, we shall be speaking about our alliance inside," Morgan said behind her veil as she opened the door.

The both us stepped inside, and Avenger saw Kariya sitting in a chair looking not like a wreck about to die any moment now, but his face still looked messed up, and his hair was still white.

"Hello Avenger, my name is Kariya Matou, Master of Caster and I hope we can talk about an alliance between us." Well, he was rather formal, but Avenger guessed that Morgan had told the Journalist to be polite towards him. "Please take a seat, there is fresh tea if you want it if you're able to drink with how you look?"

"Why thank you, Master of Caster, this is armor, and I can remove it, but I only will if you promise that I won't be attacked if I decline your offer," Avenger said.

"No of course not, I'm not Tokiomi. I treat those under my roof with the care and respect." And there was the Kariya he knew. He could feel the hatred and bitterness in his voice when he said Tokiomi's name.

"I shall take your word for it." At that Avenger removed the Wailing Armor and sat down in the chair in front of Kariya and Morgan who had taken a seat right next to her Master.

Avenger poured some of the tea for himself, to drink. Well, really not for his sake but rather for Salieri's since he like the taste of it. He could feel the world through Avenger, so even in their current state, his existence wasn't just a devil on Avenger's shoulder.

"Well, Matou, Caster if we're going to have an alliance there is some information that I have, that you must need to know." Yes, he would have to tell them all of it he was going to et them on his side. Avenger was thankful that he had indeed replaced the Berserker Class and not the Caster one.

Now he could actually actualize the plans he had discarded before. And thankfully it was a competent Caster that could accomplish what he needed her to. Based on what he could analyze from her stats.

"And what is that Avenger?" Morgan asked.

"As you might have already figured out my presence in this war is an anomaly, I have taken the place of the Berserker Class. And in addition to that, I'm not a true Servant I'm a Demi/Pseudo-Servant don't know which is applicable." Avenger saw Kariya's eyes widen, but he couldn't see Morgan's due to the veil. But he got a feeling of intrigue. "In addition, there is the fact that I'm not from this universe." That statement was met by more shock as Avenger explained everything to them. He just hoped that would go with his plan.

Xxx

Avenger stood in and looked out the window in the room he had been given by Kariya to stay in while the War was happening.

He had told everything he could and knew to the Master and Servant pair, about how he came from another Universe and knew about everything due to this entire thing being fiction in his World.

Though Kariya had been more pissed about the whole Angra Mainyu inside the Grail, than knowing his entire than knowing he hadn't saved Sakura in the original timeline. That even if he had won the Grail, and wished to save Sakura using it, he would have been screwed.

But Avenger felt great about himself, he had managed to secure a powerful ally.

Avenger turned around. "Is there something you wish to speak to me about Caster?" Avenger asked the woman that had entered his room.

"Yes, there are a few things I wish to ask you Avenger, and I take it you know who I am?" She asked.

"Yes, Morgan Le Fay, the Black Witch of Britain. But there is something I wish to ask you too. With your dear sister having been summoned into the war what do you intend to do?"

"Nothing," Morgan answered.

Avenger's brows rose at that. "I had thought you would torment her once again, to fulfill your wicked desires or rape her in her sleep again?" Though Avenger saw Morgan's body cringe at the last one.

Does she actually regret what happened?

"No, I do not wish ill will upon Arturia anymore. I believe that I have, what is the modern words ´mellowed out` after working with little Charles and taking care of him. Along with living for another thousand years after her death to think about what I had done. For at the end, I had gotten my revenge. And I just felt hollow afterward. But what I came here to ask, with your outside knowledge do you know what Arturia's wish is?" She asked.

Avenger had to laugh a little bit, he had not expected this from her.

"Yes, she wishes to redo her reign due to how it ended and when at death she would become a Counter-Guardian after death. Due to the fact, that is not Heroic Spirit Arturia down there it's her body summoned from the Fields of Camlann by the World." Avenger explained as best as he could for he couldn't quite remember what the exact circumstances were regarding Arturia's current situation.

"What? Urgh, that idiot girl always doing something reckless." Morgan cursed.

"And to make it worse even if the Grail wasn't corrupted, and it fulfilled her wish Camelot would still fall. And if did become an eternal paradise, that Timeline would be culled." Avenger said.

"Hmm, that outside knowledge is quite unfair. That is something most Magi doesn't know is a thing, and I know of it due to my Fairy Nature." Morgan complained. Yes, she was half fairy wasn't she?

"Anyway, Morgan do you think that you're able to take apart the Greater Grail and remove Angra Mainyu from the equation?" Avenger asked the Magus.

"Yes, I just need access to the Lesser Grail so I will set up shop down in the caverns to start working on it immediately."

That was good, that was very good.

"The Lesser Grail would be the Homunculus pretending to Saber's Master. Though it's just the heart that is needed, so could you give her a new one?" Avenger asked.

"I could easily, but why should I do that?" Morgan asked.

"She has a daughter, and I would rather have the family, specifically her, go through unnecessary tragedy. When I'm fully capable of preventing it." He answered.

"That is fine, but if I do this, you owe me a favor."

"Fine, just say when you want to cash it."

"I shall do that, though Avenger you know my name, I, however, do not know yours."

"Well, I guess that is fair, the Heroic Spirit within me is Salieri," Avenger answered.

"I did not ask for that, I asked for your name, I could care less for the Servant you have fused with." Morgan placed her hands on her hips.

"It's Ander, my real name is Anders." He answered her.

"Thank for telling me Anders it is appreciated. I will be talking to you tomorrow along with my Master, in how to deal with the Einzberns." At that, she turned around and left Avenger's room.

"Did, she just shake… Nah, I imagined that I should really go to bed now." Avenger said to himself, as he stripped himself.

" _Ah, you did not Master."_ Came Salier's voice as Avenger laid down on the bed.

Pffth. As he would ever attract somebody, especially somebody like her.

Xxx

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	5. Chapter 5 - Taken

"So, what can I help you with," Avenger asked the small form of Sakura Matou formerly Tohsaka as she entered lounge where I had been playing on the grand piano. This was the first time Avenger saw her since he had arrived in the mansion. Having missed each other through the entire day. It was rather comedic in hindsight, at least he thought so himself.

"I wanted to know who you were, are you a Servant like Caster?" Sakura asked.

"Yes, I am. I am Avenger, now who are you little one, and how did you know I was a Servant?" Avenger asked so that she could formally introduce herself. And he wasn't currently wearing his armor.

"I'm Sakura I know because you feel just like her." She answered. S

So she was able to sense the fact that he was a Servant, probably something to do with her Imaginary Numbers.

"Well, aren't you talented." He praised her, which caused the girl to smile a little. It made Avenger happy to see the life in her eyes.

"Thank you, but I guess you're going to help Uncle win the Grail War right?" Sakura was very smart for a six-year-old wasn't she?

And that's the blazing anger returning.

"I am his and Caster's ally in the War. Though is there something else you wanted from me Sakura." Avenger asked.

"Can you play the piano again? It sounded really good."

"Sure thing is there anything you to hear specifically?" He asked the young Magus.

"Nothing particularly." She answered.

"You might enjoy this," Avenger said as his fingers hit the piano. "Twinkle twinkle, little star." He began to sing, and Sakura joined him, giggling as Avenger switched to different songs.

"I see that you two are enjoying yourself," Morgan said as she entered the lounge after they had been playing for half an hour now. "I'm sorry Sakura, but I have to borrow your new friend now. We have a job to do."

Yes, it was the third night of the Holy Grail War now wasn't it.

"I see you later Mr. Avenger," Sakura said as she left the room, leaving only he and Morgan inside.

"Thank you for saving her and giving her hope." He thanked the Caster.

"You're welcome."

"Now have you finished your preparations?" Avenger asked.

"I did we are ready to commence our little now."

"Great let's go and kidnap us an Einzbern." Though as he said that his thought came to a halt. Well as they said imitation was the sincerest form of flattery.

"Is something wrong?"

"It's nothing I just realized something, but it has nothing to do with our current situation. And I remember the plan, I distract your Sister and her Master you get Irisviel." Avenger summoned up their bear ass plan.

Morgan just smiled in response.

Xxx

Arturia sat on a sofa in their base reading a book she had taken from the castle's library to pass the time. As her dear Master planned their next move, with Avenger putting a spinner in their original plan. Though she had learned from him (Meaning told to her by Irisviel after he had explained it to her.) that Avenger was not as big a bastard like she had originally thought then he had announced to the Servants. That he had killed his Master.

As his summoner had apparently been a Serial Killer that had been terrorizing the city, and in the process saved a child's life. Kiritsugu having apparently put two and two together and gotten the conclusion from the music he had played, and the child's description of who had saved. Cause the song he had played had been the theme song of the fictional hero that had saved him.

Which meant at least the Servant of Vengeance had a heroic inclination, and so Arturia hoped that he wouldn't try to go after Irisviel when she moonlighted as her Master.

Speaking of Irisviel, the snow-haired woman was listening to music on the radio. The wonders of modern technology to have basically a portable bard at the ready at all time. She only had Tristan.

And now she made herself sad.

Don't think about them Arturia, you won't need to feel sorry after you get the Grail and make everything right.

That was then another form of music began to reverberate throughout the Castle. It was like somebody had found a way to turn Madness itself into sound. It was so heavy and dark, so sad. Like the weight she was already feeling had been increased tenfold.

Arturia looked over at Irisviel who was now gasping and breathing heavily.

They were under attack, and Arturia knew exactly by who.

With a thought, she used the telepathic connection that existed between her and Kiritsugu, one that had rarely used. Arturia knew the man didn't like her, but she knew that he loved his wife and would do anything for her.

And with another, she stood in her armor as she left the room and headed for the source of the music, as Invisible Air concealed her blade. Though taking a single step were then they appeared. Where they hadn't been before, Arturia felt the magical energy that composed the grey looking ghosts wielding guns, rapiers, and spears that flooded the hallway. They felt exactly like Avenger had.

So the man was capable of summoning some form of familiar. So what they were nothing to he. As with a single swing of her blade a dozen had been vanquished.

As the Irisviel watched Saber leave the room, the maddening music pounded in her head. She hoped that Saber would take care of the enemy quickly. "I hope she and Kiritsugu are going to be okay."

"Them yes, you not so much." A Female voiced stated from behind, Iriviel quickly turned around to see a pale-skinned woman in a blue dress, with a black veil in front of her face as he vision went black.

Xxx

Avenger's fingers moved like he was playing on an air piano and he kinda was, but unlike others, his did produce music. And the current track he was playing allowed him to summon the Men in Grey to do his bidding.

Their current job was to distract and separate Saber from Irisviel and to keep Kiritsugu from defending her as Morgan took the homunculus from the castle.

And now for the finisher.

He slammed his fingers down creating a deafening tone, that forced his Men in Grey to rush at Arturia as she appeared before him, but the Saber applied Mana Burst and dodged the attack.

No fair she didn't have Evade.

"Hello Saber, what a wonderful night it is," Avenger said paying no heed to the scowl on the miniature woman's face.

"Avenger, what are you doing here?" She asked as she pointed the invisible Excalibur at him.

"I am here to play some music of course King of Knights." He chimed. "But you really shouldn't be that concerned about me Saber. You should be more concerned about young Mrs. Einzbern." He told her.

"You! What have you done!"

"Me nothing. My partner Caster, however, you might find that your princess is in another castle." He told her.

"Argh!" Arturia shouted as she was about to attack him as he saw her face contort to one of anger. But before she could hit him, he snapped his fingers, which caused her to crawl to a halt and throw up as she collapsed to her knees as she clutched her head.

"Magic Resistance is surprisingly easy to work around as long as you do it through the correct medium. Take this as a warning Saber never underestimate a sound manipulator. Though good news your Master will have his wife back soon." Avenger said as he left the King of Knights to wither on the ground.

" _My Master you certainly have a knack for this. I would have never thought my powers as an Avenger compatible one such as you. And that song that heavy piano of despair and Madness. To think that this modern world could come up with a piece like that."_ Came the praise from Salieri.

"I guess, though I wish I would have summoned you like a normal person so that I could interact with you personally. Though that trick only worked because that is her actual physical body and not a spiritual one."

" _I wish that had been the case, but I'm not complaining about my current situation. Now return to your witch and purge my fellow Avenger from the Grail."_ The ghostly form of Salieri vanished returning to Avenger's subconscious.

It did not take long for him to travel to the underground cavern where the Greater Grail was located and where Morgan had set up shop.

And it seemed she was already underway with construction of the new container for the Lesser Grail if the fetus in the giant wat was any indication.

"My these Einzbern Homonculi are certain of good quality." She said as he approached her as she looked over the sleeping Irisviel.

"So, we just wait for the replacement to grow, and switch the hearts. And after I purged it, the Grail is basically ours."

"Not yours?" Avenger asked, he really had no desire for the thing even if Morgan purged the worlds angriest mango from it.

"Hmm, Kariya has no desire for the thing his wish of saving Sakura from the worm has been fulfilled now he just wants to win to keep it from Tokiomi, as a big middle finger. So its wishes are ours to use. I just want a body again, the soon to be future seems like a promising place to live in." Like she needed it to do just that. "What about you Avenger?"

"Me I have no wish, but I do intend to fulfill Salieri's."

"Oh that is a surprise, now I need to get to work in the meantime you just relax, while the others take each other out," Morgan said with a dark chuckle.

True that was the best course of action, but he wanted to attend a certain Banquet, but this time make it a real one, and not just shitty barreled wine.


End file.
